ON THE SPACING OF RICE UNDER THE DIRECT SOWING CULTURE

Abstract

This experiment was carried out for three years (1947, 1948 and 1949) to know the adequate spacing of rice plants under sowing. We set up two plots, direct sowing and transplanting, the former divided into the following three plots, i. e. with 60, 120 and 240 plants per "tsubo" respectively and the latter into two plots, i. e. with 60 and 120 plants per "tsubo" The results were summarized as follows: (1) The rate of growth of plants sown directly was higher than that of plants tsansplanted during the period of vegetative growth, but after the development of the infant ears, the transplanted plants showed rapid growth, and at the time of heading no difference of culm length was recognized between these two plots. (2) As the spacing of plants became narrower, number of culms per plant was decreased, but on the contrary number of culms per "tsubo" was increased. (In the same spacing, number of culms per plant sown directly was greater than that of transplanted.) (3) Both growth and yield of the plot having 1.5 "shaku" spacing of rows were better than that of the plots having 1.0 and 2.0 "shaku" spacing. (4) As regard to "tillering" it was observed that the plants sown directly branched out tillers from lower nodes in comparison to the case of the transplanted, and more over the case of direct sowing it was observed that the tillering loci became upper as the spacing became narrower. (5) The yield of unhulled rice of the plots of direct sowing was higher than that of transplanted irrespective of the kinds of spacing, and the narrower the space, the greater became the yield in both the direct sown and transplanted plots.